167_C-0340

Title: Physical Properties Of The Most Pristine Solar System Bodies:Transneptunian Objects And Centaurs

Scientific program: Transneptunian Objects and Centaurs were formed in the KuiperBelt, the left-over of the formation disk of our planetary system.They contain the most pristine material that originates fromabout 4.6 billion years ago and that we can observe today.However, just a very vague picture exists on their physicalproperties and their evolution over the age of the solar system.

This proposal will address the key questions on the nature ofTNOs and Centaurs:

Which taxonomic types exist among TNOs and among Centaurs?

What are the development tracks of the taxonomic types andhow do they relate to the orbit evolution of the objects?

What is the surface chemistry the objects, are theirdifferences among the objects and how do they correlatedwith the taxonomic type classification?

Which objects display the primordial chemistry of the KuiperBelt region, which don't?

Are there colour and spectral diversities and thusnon-uniformities in the surface material of a single object?

Is coma activity possible in TNOs?

What is the albedo and the size distribution of the objects?

The answers will be obtained from observations (visible andnear-IR photometry and spectroscopy) of a large, statisticallysignificant sample of TNOs and Centaurs.